1. Field of the Invention
The present invention relates to air compressors. More particularly, the present invention relates to apparatus for the removal of moisture that accumulates within the compressed air tank. Additionally, the present invention relates to check valving system whereby moisture is removed from the compressed air tank when the head pressure relief valve opens.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
An air compressor system is often pressurized with a motor-driven compressor controlled by a pressure-operated switch that senses pressure in an air receiver, such as a pressure vessel. The compressor forces compressed air through a discharge tube and a check valve which is connected to a pressure vessel. The pressure vessel serves as a reservoir for storing the compressed air. When the pressure of the compressed air being produced and stored in the pressure vessel reaches a preselected maximum level, the pressure switch shuts off the compressor motor to stop further pressurization. The lack of pressure from the compressor allows the check valve to close and prevents air from flowing from the air receiver back to the discharge tube when pressurization stops. Pressurized air would still remain in the discharge tube and the head of the compressor.
As air is consumed from the pressure vessel, the level of pressure remaining within the pressure vessel is reduced. When the pressure in the pressure vessel falls to a preselected minimum level, the pressure switch again operates the compressor to resume pressurization. However, if the remaining pressure in the discharge tube and in the head of the compressor is not removed prior to resuming pressurization, the compressor must overcome the added load from this remaining pressure in addition to the load of initiating pressurization. This can result in adverse system effects on the compressor motor such as motor stalling or electrical circuit overloading in the circuit in which the motor is stalled.
In order to prevent this, a head pressure relief valve is operated by the pressure switch to relieve the pressure from the discharge tube when the pressure within the pressure vessel rises to a preselected maximum pressure level. Typically, the head pressure relief valve is connected to the discharge tube through an additional hose, tubing or other mechanical communication means.
Various equipment systems include pneumatic components. For example, pneumatic tools comprising important class of manufacturing, construction, maintenance and repair tooling. A typical system includes a compressor, one or more pneumatic tools and a respective flexible hose connecting each tool to the compressed gas source. In addition to ambient air, other gases, such as nitrogen, are suitable in pneumatic power operations.
In manufacturing, constructing, maintenance and repair operations that use pneumatic tooling, the connecting hoses are relatively long in order to accommodate freedom of movement by the workers. The tools are somewhat portable and are tethered to the compressed gas source by these connecting hoses.
A major problem affecting such compressed air systems is the accumulation of moisture within the compressed air tank. Moisture is an inherent result of the compressing of air and, as such, a small amount of moisture will inherently accumulate within the bottom of the compressed air tank. Conventional compressed air systems will include a drain connection at the bottom of the compressed air tank. In normal operations, after a certain period of time, a worker will open the drain so as to allow the moisture to be removed from the compressed air tank. Unfortunately, since the drain is located at the bottom of the tank and it is often in an inconvenient location, workers will tend to ignore this requirement and will allow further moisture to be accumulated within the compressed air tank. As such, a need has developed so as to be able to remove moisture from the interior of compressed air tanks without the need for the opening of the drain connection.
If an excessive amount of moisture should accumulate within the compressed air tank, then the passage of moisture, along with compressed air, can often effect damage to pneumatic tools and to the system in general. Fundamentally, the accumulation of moisture will reduce the amount of compressed air that can be accumulated within the compressed air tank. As such, the compressor pump will have to operate more often than desired in order to maintain the pressure within the tank at a desired level. Ultimately, system failure can occur if too much moisture is accumulated within the compressed air tank. Once again, it is important to be able to remove the accumulated moisture within the compressed air tank in a simple, convenient and effective manner.
A check valve is used so as to stop the passage of air outwardly of the head pressure relief valve when a sufficient amount of pressure is relieved from the compressor pump and from the compressed air tank. Unfortunately, the action of this check valve does not allow any moisture to be emitted through the head pressure relief valve. As such, a need has developed so as to delay the action of the check valve in a proper manner so that moisture and air can be released through the head pressure relief valve.
In the past, various patents have been issued relating to check valves and air compressor system. For example, U.S. Pat. No. 3,224,118, issued on Dec. 14, 1965 to J. V. Hutelmyer, describes an air brake tank. The tank has a single, closed shell with a partition which divides the interior of the tank into wet and dry compartments. A small, compact, ball-type check valve is mounted on the tank in a position to communicate with both compartments in the vicinity of the partition. When air is required in the dry compartment, the ball is blown off of its seat by the air pressure in the wet compartment and to permit the compressed air in the wet compartment to pass freely into the dry compartment. In the event of any air reduction in the wet compartment, the ball immediately seats itself in response to air compressor in the dry compartment and automatically locks the air in the dry compartment.
U.S. Pat. No. 3,841,349, issued on Oct. 15, 1974 to T. J. Todd, shows a trickle rate fluid outlet. A valve cage extends upwardly from a pressurized fluid source and has a lower inlet valve seat and an upper outlet valve seat. The starting of flow through the cage lifts a ball from the lower seat to close the upper seat but lifts the ball at only a moderate rate with a prolonged initial purging of the valve cage.
U.S. Pat. No. 3,732,890, issued on May 15, 1973 to D. G. Smith, describes an unloader valve for air compressors. This unloader valve is provided at the outlet of an air compressor for subjecting the compressor to a limited back pressure until the compressor gains enough speed to be able to pick up the full load. Thereafter, the device operates to open the passage to the compressed air tank. This device is provided with a casing having a main passage therethrough in which there is positioned a check valve which controls the passage to the compressed air tank. This device also includes a cylinder which is connected to the casing by a restriction hole and the cavity of this cylinder is normally open to the atmosphere. A valve member is provided in the cylinder cavity responsive to the flow of air into the cavity through said restriction hole. This valve member functions to close an exhaust hole when the air compressor approaches delivery of normal compressed air output.
U.S. Pat. No. 3,845,778, issued on Nov. 5, 1974 to R. J. Bridigum, shows an automatic drain valve for periodically draining accumulated moisture condensation and other contaminants from a fluid pressure storage reservoir upon a reduction of the pressure of the fluid in the reservoir from a chosen pressure to a lower chosen pressure independently of a governor device which controls the operation of a fluid compressor that supplies fluid under pressure to the storage reservoir.
U.S. Pat. No. 4,069,840, issued on Jan. 24, 1978 to Brown et al., shows a check valve for permitting fluid flow in one direction and for preventing flow in the reverse direction. This check valve has a tubular body having a longitudinal flowbore therethrough. An annular seat is located within the flowbore. An inclined cylindrical pocket communicates with the flowbore. A ball member is movable between the pocket and sealing engagement with the seat in the flowbore to permit fluid to flow in one direction but blocking flow in the reverse direction.
U.S. Pat. No. 4,633,681, issued on Jan. 6, 1987 to R. C. Webber, teaches a refrigerant expansion device that has a housing with an inlet tube for connection to the liquid line from the condenser and an outlet tube for connection to the evaporator. The outlet tube has a valve-like seat in its inner end and orifice grooves formed in the seat. A steel ball is movably disposed in the housing such that liquid refrigerant during compressor operation forces the ball into the seat so as to form an expansion orifice between the ball and the seat.
U.S. Pat. No. 6,698,446, issued on Mar. 2, 2002 to J. P. Cornwell, provides a check valve with an elongated body and a hole extending from an inlet end to an outlet end. A piston assembly is mounted within the body. This piston assembly includes a piston, a check valve and a piston spring. The piston spring biases the piston to a first piston location preventing air from flowing from the inlet toward the outlet end. The check valve seal can be positioned on the piston assembly to seal against either a check valve seat or the inside diameter of the hole to restrict air flow when the piston is in the first piston location. Movement of the piston to a downstream piston location can remove the check valve seal from the check valve seat so as to allow air to flow from the inlet end toward the outlet end.
U.S. Pat. No. 7,069,946, issued on Jul. 4, 2006 to E. I. Clare, shows a slow-release check valve for a pneumatic system. This slow-release check valve has a compressed gas source and a pneumatic device. The pneumatic devices includes a body with a proximal supply end and a distal power end. Supply and power couplings are mounted on the body supply and power ends respectively and are adapted for coupling with a compressed gas source and a pneumatic device. The body includes a passage with a frustoconical configuration with a minimum-diameter supply end adjacent to the supply coupling and a maximum-diameter power end adjacent to the power coupling. A ball is movably located within the passage and engages the body in a closed position. The ball is biased towards its closed position by a spring. For power operation, the ball is in an open position whereby gas flows around same. Disconnecting the hose causes the ball to move to its closed position and allows compressed gas to slowly dissipate from the disconnected hose.
U.S. Patent Publication No. 2005/0121084, published on Jun. 9, 2005 to B. Andersson, shows a ball check valve that comprises a housing having walls defining a fluid inlet, a fluid outlet, and a chamber communicating with the inlet and with the outlet. The ball check valve includes a spherical hollow ball housing a plurality of spherical shock absorbing members that stabilize the spherical hollow ball during operation of the valve. The spherical hollow ball moves between a first, flow-impeding position adjacent the inlet and a second position spaced from the inlet laterally of a fluid passageway in the chamber.
It is an object of the present invention to provide an apparatus for effectively removing moisture accumulation from an interior of a pressure tank.
It is another object of the present invention to provide an apparatus that allows moisture to be released through the head pressure relief valve by delaying the opening and closing of the ball-type check valve.
It is a further object of the present invention to provide an apparatus that effectively prevents moisture accumulation from occurring in the pressure tank.
It is another object of the present invention to provide an apparatus which eliminates the requirements for workers to open and close the drain associated with the compressed air tank.
It is still a further object of the present invention to provide an apparatus that effectively removes moisture from the interior of a pressure tank and minimizes the power requirements of the compressor pump.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.